The present invention relates to a library of hard disk drives, such as for use as mass storage for mainframe or other host computers. More particularly, the invention relates to a library of hard disk drives with an interface for emulating other forms of mass storage so that manipulation and control of multiple hard disk drives in the library is transparent to the host computers.
Large scale computing devices often employ stores of optical or tape storage media as part of a strategy for storing very large amounts of data at relatively low cost. The strategy may also provide redundancy to further improve performance and reliability. The optical or tape storage media is typically stored in a shelved space known in the art as a library. Individual storage units, such as optical discs or tape cassettes, are stored on dedicated shelves or in dedicated bins in the library. As such libraries were originally provided, a human operator would be signaled by a host computer to retrieve the storage unit from a particular shelf or bin and install the storage unit in a drive mechanism that is electrically coupled to the host computer, permitting the host computer to read from and write to the selected storage unit.
An improvement to the library replaced the human operator with a robotic picking mechanism. The picking mechanism or xe2x80x9cpickerxe2x80x9d is adapted to grasp a memory storage medium and move the medium within the space of the library, carrying the medium between its place of origin and a destination. Such a picker for optical disk media is described in Dimitri et al., U.S. Pat. No. 5,377,121, which is herein incorporated by reference in its entirety.
Problems remain with the library as it is currently being practiced. Particularly, the optical media provides relatively slow reading and writing, while tape media provides relatively slow random access. Moreover, there is a need for providing communications with the library that render the internal operation of the library transparent to host computers accessing library resources. This may further call for the ability of the library to emulate some other form of mass storage with which the host computer is accustomed.
Accordingly, there is a need for a library of hard disk drives with transparent emulating interface that provides for decreasing the time required for reading data from and writing data to storage media in the library, that provides for transparent operation relative to one or more host computers requesting data, and that provides for emulating the characteristics of a selected storage device.
Disclosed is a library of hard disk drives with transparent emulating interface according to the present invention for coupling one or more of a plurality of hard disk drives to one or more host computers using the library. The hard disk drives are shelved in associated storage locations in the library. A library controller translates the logical address of a requested hard disk drive known to the requesting host computer to a physical address or location within the library. A picker preferably mounts the requested disk drive to a destination receptacle which may be part of a backplane of the library, and the controller accesses the hard disk drive. Library operation is transparent to the host computer, the library emulating a selected type of storage device.
Therefore, it is a principal object of the present invention to provide a novel and improved automated library of storage media.
It is another object of the present invention to provide a library of hard disk drives that provides for decreasing the time required for reading data from or writing data to storage media in the library.
It is still another object of the present invention to provide a library of hard disk drives with a transparent emulating interface that provides for transparent operation relative to one or more host computers requesting data.
It is yet another object of the present invention to provide a library of hard disk drives with transparent emulating interface that provides for emulating the characteristics of a selected storage device.